One-pot synthesis of pyrazolotriazole photographic dye forming color couplers and coupler intermediates

ABSTRACT

Photographic pyrazolotriazole dye forming coupler compounds of coupler intermediate compounds can be readily prepared in a single reaction medium by reacting certain pyrazolotriazole compounds with nitro-substituted aromatic compounds in the presence of a formate salt and a transition metal catalyst. This salt hydrogenates the nitro group and the carbonate by-product induces reaction of the resulting amine with the pyrazolotriazole compound. Yields and purity are high, and reaction time is reduced with the specific set of conditions and reactants, and environmental impact from waste is reduced. In addition, isolation of aromatic amine intermediates is avoided. The resulting pyrazolotriazole compounds can be used themselves as photographic dye forming couplers or further reacted to prepare useful coupler compounds for photographic use.

This application is a divisional application of Ser. No. 09/203,459,filed Dec. 2, 1998.

COPENDING APPLICATION

Reference is made to copending and commonly assigned U.S. Ser. No.09/204,444 filed on even date herewith by Bose, Valente, Aimino andDeMejo and entitled "Synthesis of Pyrazolotriazole Photographic DyeForming Color Couplers and Intermediates".

FIELD OF THE INVENTION

This invention relates to a method of preparing pyrazolotriazolecompounds that are useful as photographic dye forming couplers or asintermediates for the preparation of pyrazolotriazole photographic dyeforming coupler compounds. In particular, it relates to a method ofpreparing certain 1-H-pyrazolo[5,1-c]-1,2,4-triazole compounds in asingle-reaction medium. This invention is useful in the photographicindustry.

BACKGROUND OF THE INVENTION

Color photographic silver halide materials are used to provide colorimages with the use of certain dye forming compounds that are usually inthe various photosensitive silver halide layers of the materials. Thesedye forming compounds are conventionally known as "dye forming couplers"and are reactive with suitable oxidized forms of color developing agentsused during photoprocessing to provide the desired dye images. Sincemost of such silver halide materials (such as color negative films andcolor papers) provide images based on what is known in the art as"subtractive color mixing", they typically include dye forming couplersthat will provide cyan, yellow and magenta dyes in the appropriatephotosensitive layers.

PyrazoIotriazoles have been known to be useful magenta dye formingcouplers for some time, and various processes are known for preparingthem, all of which usually include various chemical reactions taken inspecific order. Such processes add functionality that defines thedesired dye forming coupler early in the synthesis. These processesresult in the lack of generality of the process and the need to makedifferent intermediates for different dye forming coupler end products.

It is well known in the art [for example, U.S. Pat. No. 5,183,728(Romanet et al), U.S. Pat. No. 5,457,210 (Kim et al) and U.S. Pat. No.5,565,572 (Potenza et al)] that compounds defined by Formula IV beloware known to be photographic dye forming couplers, as well as precursorsto other photographic dye forming couplers.

It is known from EP 779,543 (Bose et al) that one common synthetic routeto these types of compounds involves the high pressure catalyticreduction of a nitro aromatic compound (shown as Formula II below) usinghydrogen to form an aromatic amine of Formula III, and then reaction ofthe aromatic amine with a compound of Formula IV under basic conditions.This is generally a two step process involving the isolation andhandling of the aromatic amine of Formula III. ##STR1##

There are several disadvantages to such a two-step process. It includesincreased cycle time due to increased handling requirements, increasedair emissions if drying of the intermediate is required, and increasedtotal volume of solvent needed. In addition, with this particularsynthetic route, two different types of reaction vessels are needed. Thecatalytic hydrogenation of the first step requires specially designedhigh pressure equipment, while the displacement second reaction can becarried out in a standard reaction vessel. Additionally, this methodrequires the use of highly flammable hydrogen gas that presents acritical safety issue.

It is a desire in the industry to identify a chemical process that wouldtransform aromatic nitro compounds of Formula II and the compounds ofFormula IV into coupler precursors or couplers of Formula I in one stepusing one reaction vessel. It is also desired to accomplish this taskwith high chemical yield, high purity, short cycle time, low solventusage, increased safety and minimal negative environmental impact.

One possible alternative to catalytic hydrogenation is a hydrogentransfer reaction [as described for example by Johnstone, et. al, Chem.Rev., 1985, 85, 129, Entistle, et. al, J. Chem. Soc., Perkin I, 1977,443, and U.S. Pat. No. 5,041,605 (Huson et al)]. There are many possiblehydrogen sources that can be used but each results in a differentby-product.

Thus, there remains a need for an improved, single reaction mediumsynthesis of pyrazolotriazole dye forming coupler intermediates.

SUMMARY OF THE INVENTION

These problems are overcome with a method for preparing apyrazolotriazole dye forming coupler compound or coupler intermediatecompound of Structure I in a single reaction medium, the methodcomprising reacting a nitro-substituted aromatic compound NO₂ --Ar witha compound of Structure IV in the presence of a formate salt, ##STR2##wherein Ar is an aromatic group (as defined below), R₁ is an alkyl,aryl, alkoxy, aryloxy or amido group, R₂ is hydrogen or an alkyl or arylgroup, X is hydrogen or a coupling-off group or a precursor thereof, andY is a leaving group that is capable of being replaced by anelimination-addition reaction,

whereby the nitro-substituted aromatic compound is converted to thecorresponding aromatic amine that is then, without isolation from thesingle reaction medium, reacted with the compound of Structure IV.

This invention also provides a method for preparing a pyrazolotriazoledye forming coupler compound comprising:

A) forming a compound of Structure I as described above, and

B) further reacting the compound of Structure I obtained in step A.

The present invention is advantageous because it provides a dye formingcoupler compound or coupler intermediate compound in high yield andpurity using a synthesis that can be carried out in a single reactionmedium using a nitro-substituted aromatic compound. In addition, themethod of this invention is safer since the use of highly flammablehydrogen is avoided, and the impact upon the environment is minimizedbecause less solvent is used and there are less by-products fordisposal.

These advantages are achieved by the use of formate salts as thehydrogen donor in conversion of the nitro-substituted aromatic compound.The by-products from use of the formate salt in the first step arecarbonate and bicarbonate salts that are very effective at promoting thesecond step, the displacement reaction to form a Structure I compound.It is therefore possible to run these two steps sequentially, in onereaction vessel, with no isolation of the intermediate aromatic amine.The combination of the hydrogen transfer reaction and the displacementreaction into one step was a surprising result because most otherhydrogen transfer donors do not yield basic by-products that willpromote the displacement reaction.

The present invention can be used to prepare pyrazolotriazole dyeforming color couplers that are reactive with oxidized photographiccolor developing agents to provide photographic dyes. Such couplercompounds may be useful in various photographic silver halide materials,or in photochemical processing solutions that are useful for providingcolored images from such materials. Alternatively, the compoundsprepared using the present invention may be further reacted as oneskilled in the art would readily understand, to add ballast groups,coupling off groups or other reactive groups. The resulting compoundscan then be used in any suitable manner.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a method for converting nitro-substitutedaromatic compounds of Structure II to aromatic amines of Structure IIIand then to coupler intermediates of Structure I by reaction withcompounds of Structure IV in a single reaction medium that includes aformate salt. The two reactions in the single step process are generallycarried out using the conditions described below. Upon completion of thesecond reaction, the resulting salts can be removed by filtration or byadding a water-immiscible organic solvent and washing with water or amildly acidic solution. Any organic solvent remaining in reaction mediumcan be removed by distillation.

The general reaction scheme of the invention is shown as follows:##STR3##

Ar is any suitable carbocyclic or heterocyclic aromatic group havingfrom 6 to 14 carbon, nitrogen, oxygen or sulfur atoms in the ringstructure, and one or more substituents (up to 4, defined below) on thearomatic ring that do not interfere with the reactions or end use of thecoupler intermediates or dye forming couplers.

In Structure IV, R₁ can be, but is not limited to, any of the groupsconventionally found in this position on corresponding photographic dyeforming couplers or precursors thereof. For example, useful R₁ groupsinclude, but are not limited to, substituted or unsubstituted alkylhaving from 1 to 12 carbon atoms (for example, methyl, ethyl,methoxymethyl, isopropyl, t-butyl, n-pentyl, n-hexyl, decyl, dodecyl,benzyl and phenethyl), substituted or unsubstituted cycloalkyl having 5to 12 carbon atoms in the ring (or combination of rings, such ascyclopenyl, cyclohexyl and 4-methylcyclohexyl), substituted orunsubstituted alkoxy having 1 to 12 carbon atoms (such as methoxy,2-ethoxy, isopropoxy, methoxymethoxy and benzoxy), substituted orunsubstituted allyloxysulfonyl (wherein the alkyl portion has 1 to 12carbon atoms as defined above), substituted or unsubstitutedalkylsulfonyl (wherein the alkyl portion has 1 to 12 carbon atoms asdefined above), substituted or unsubstituted aryl having 6 to 12 carbonatoms in the aromatic ring (or combination of rings, such as phenyl,p-methylphenyl, 3-methoxyphenyl, naphthyl, tolyl, halophenyl groups,nitrophenyl groups, aminophenyl groups, carboxyphenyl groups,methoxycarbonylphenyl groups, hydroxyphenyl groups and ethoxyphenylgroups), substituted or unsubstituted aryloxy having 6 to 12 carbonatoms in the aromatic ring (or combination of rings, such as phenoxy,p-methylphenoxy, halophenoxy groups, aminophenoxy groups andalkylphenoxy groups), substituted or unsubstituted aryloxysulfonylwherein the aryl portion is as defined above, and substituted orunsubstituted arylsulfonyl wherein the aryl portion is as defined above.

R₁ can also be an acyl group (such as acetyl or --OCOCH₂ CH₃),substituted or unsubstituted amino (such as substituted or unsubstitutedalkyl and arylamines), amido (such as methamido, 2-ethylamido andt-butylamido), substituted or unsubstituted alkylthio wherein the alkylportion has 1 to 12 carbon atoms (as defined above), substituted orunsubstituted arylthio wherein the aryl portion has from 6 to 12 carbonatoms in the ring structure (as defined above), or a substituted orunsubstituted heterocyclyl having from 5 to 12 carbon, nitrogen, oxygenor sulfur atoms in the heterocyclic ring (or combination of rings).Useful heterocyclyl groups include, but are not limited to, pyridyl,pyrimidyl, pyrazolyl, pyrrolyl, oxazoyl, thiazolyl, furanyl andthiophenyl.

In preferred embodiments, R₁ is a substituted or unsubstituted alkyl,substituted or unsubstituted aryl, amido, substituted or unsubstitutedacyl, substituted or unsubstituted alkoxy or substituted orunsubstituted aryloxy group as defined above (such as methyl, ethyl,isopropyl, t-butyl, methoxy, ethoxy, phenyl, phenoxy, a methylphenylgroup, a chlorophenyl group, a nitrophenyl group, a methoxyphenyl groupand t-butylamido). Amido and acyl are the least preferred of suchgroups. Most preferably, R₁ is a substituted or unsubstituted alkylgroup, such as substituted or unsubstituted methyl, ethyl, isopropyl andt-butyl groups, or a phenyl or phenoxy group.

R₂ is hydrogen, or a substituted or unsubstituted alkyl, substituted orunsubstituted aryl or substituted or unsubstituted heterocyclyl group,as defined above for R₁ (obviously, R₁ and R₂ can be different groups).Preferably, R₂ is a substituted or unsubstituted aryl group (such asphenyl, chlorophenyl groups, methylphenyl groups, methoxyphenyl groups,nitrophenyl groups) or a substituted or unsubstituted alkyl group having1 to 4 carbon atoms (such as methyl, ethyl, isopropyl, isobutyl andt-butyl groups). More preferably, R₂ is a substituted or unsubstitutedphenyl group (for example, m- or p-nitrophenyl) or substituted orunsubstituted alkyl group (for example, a methyl, ethyl or t-butylgroup). Unsubstituted phenyl and methyl are the most preferred R₂groups.

Also within Structure IV, X is hydrogen or a coupling off group or aprecursor thereof. Such coupling off groups are well known in thephotographic art as groups that can be replaced by oxidized colordeveloping agent during photographic processing (that is, colordevelopment). Such groups can determine the chemical equivalency of acoupler, that is whether it is a 2-equivalent or a 4-equivalent coupler,or modify the reactivity of the coupler. The presence of hydrogen at thecoupling site ("X") provides a 4-equivalent coupler, and the presence ofthe coupling off group usually provides a 2-equivalent coupler.

Representative coupling off groups (or precursors thereof) include, butare not limited to, halo (such as chloro or bromo), substituted orunsubstituted alkoxy having 1 to 12 carbon atoms (as defined above forR₁), substituted or unsubstituted aryloxy having 6 to 12 carbon atoms inthe aromatic ring (or combination of rings, as defined above for R₁),substituted or unsubstituted hetero-oxy (that is a heterocyclyl attachedthrough an oxy group) having from 5 carbon and heteroatoms in theheterocyclyl ring(s), substituted or unsubstituted alkylthio wherein thealkyl portion has from 1 to 12 carbon atoms as defined above for R₁,arylthio wherein the aryl portion has from 6 to 12 carbon atoms asdefined above for R₁, heterocyclyl as defined above for R₁, sulfonyloxy,acyloxy, acyl, sulfonamido, mercaptopropionic acid, phosphonyloxy andarylazo.

Preferably, X is hydrogen, halo, phenoxy, a substituted or unsubstitutedalkylthio group (such as methylthio or carboethoxyethylthio) or asubstituted or unsubstituted arylthio group (such as phenylthio). Mostpreferably, X is hydrogen, chloro, phenoxy or carboethoxyethylthio.

Y is a leaving group that is capable of being replaced in anelimination-addition reaction. Such groups include, but are not limitedto, halo, hydroxy, substituted or unsubstituted alkoxy having 1 to 12carbon atoms (as defined above for R₁), substituted or unsubstitutedaryloxy having 6 to 12 carbon atoms in the aryl portion (as definedabove for R₁), substituted or unsubstituted acyloxy (such as acetoxy and--OCOalkyl_(C2-C8)), substituted or unsubstituted alkylsulfonyloxy orarylsulfonyloxy (as defined above for R₁). Preferred Y groups include,but are not limited to, halo, and substituted or unsubstituted aryloxy,acyloxy and alkoxy groups. More preferably, Y is halo (such as chloro),substituted phenoxy (such as p-nitrophenoxy) or an acetoxy group.Addition-elimination reactions are described for coupler synthesis inU.S. Pat. No. 5,183,728 (noted above).

Unless otherwise specifically stated, substituent groups that may besubstituted on compounds of Structures I-IV described herein include anygroups, whether substituted or unsubstituted, that do not destroyproperties necessary for photographic utility. When the term "group" isapplied to the identification of a substituent containing asubstitutable hydrogen, it is intended to encompass not only thesubstituent's unsubstituted form, but also its form that is furthersubstituted with any group or groups as herein mentioned. Suitably, thegroup may be halo or may be bonded to the remainder of the molecule byan atom of carbon, silicon, oxygen, nitrogen, phosphorous, or sulfur.The substituent may be, for example, halo (such as chloro, bromo orfluoro), nitro, hydroxyl, cyano, carboxyl, or groups which may befurther substituted, such as alkyl, including straight or branched chainalkyl [such as methyl, trifluoromethyl, ethyl, t-butyl,3-(2,4di-t-pentylphenoxy) propyl, and tetradecyl], alkenyl (such asethylene and 2-butene), alkoxy [such as methoxy, ethoxy, propoxy,butoxy, 2-methoxyethoxy, sec-butoxy, hexyloxy, 2-ethylhexyloxy,tetradecyloxy, 2-(2,4-di-t-pentylphenoxy)ethoxy and 2-dodecyloxyethoxy],aryl (such as phenyl, 4t-butylphenyl, 2,4,6-trimethylphenyl andnaphthyl), aryloxy (such as phenoxy, 2-methylphenoxy, α- orβ-naphthyloxy and 4-tolyloxy), carbonamido [such as acetamido,benzamido, butyramido and tetradecanamido,α-(2,4-di-t-pentyl-phenoxy)acetamido,α-(2,4-di-t-pentylphenoxy)butyramido, α-(3-pentadecylphenoxy)-hexanamidoand α-(4-hydroxy-3-t-butylphenoxy)-tetradecanamido],2-oxo-pyrrolidin-1-yl, 2-oxo-5-tetradecylpyrrolin-1-yl,N-methyltetradecanamido, N-succinimido, N-phthalimido,2,5-dioxo-1-oxazolidinyl, 3-dodecyl-2,5-dioxo-1-imidazolyl, andN-acetyl-N-dodecylamino, ethoxycarbonylamino, phenoxycarbonylamino,benzyloxycarbonylamino, hexadecyloxycarbonylamino,2,4-di-t-butylphenoxycarbonylamino, phenylcarbonylamino,2,5-(di-t-pentylphenyl)carbonylamino, p-dodecyl-phenylcarbonylamino,p-toluylcarbonylamino, N-methylureido, N,N-dimethylureido,N-methyl-N-dodecylureido, N-hexadecylureido, N,N-dioctadecylureido,N,N-dioctyl-N'-ethylureido, N-phenylureido, N,N-diphenylureido,N-phenyl-N-p-toluylureido, N-(m-hexadecylphenyl)ureido,N,N-(2,5-di-t-pentylphenyl)-N'-ethylureido, and t-butylcarbonamido,sulfonamido (such as methylsulfonamido, benzenesulfonamido,p-toluylsulfonamido, p-dodecylbenzenesulfonamido,N-methyltetradecylsulfonamido, N,N-dipropyl-sulfamoylamino andhexadecylsulfonamido), sulfamoyl {such as N-methylsulfamoyl,N-ethylsulfamoyl, N,N-dipropylsulfamoyl, N-hexadecylsulfamoyl andN,N-dimethylsulfamoyl), N-[3-(dodecyloxy)propyl]sulfamoyl,N-[4-(2,4-di-t-pentylphenoxy)butyl]sulfamoyl,N-methyl-N-tetradecylsulfamoyl, and N-dodecylsulfamoyl}, carbamoyl {suchas N-methylcarbamoyl, N,N-butylcarbamoyl, N-octadecylcarbamoyl,N-[4-(2,4di-t-pentylphenoxy)butyl]carbamoyl,N-methyl-N-tetradecylcarbamoyl, and N,N-dioctylcarbamoyl}, acyl [such asacetyl, (2,4-di-t-amylphenoxy)acetyl, phenoxycarbonyl,p-dodecyloxyphenoxycarbonyl methoxycarbonyl, butoxycarbonyl,tetradecyloxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl,3-pentadecyloxycarbonyl, and dodecyloxycarbonyl], sulfonyl (such asmethoxysulfonyl, octyloxysulfonyl, tetradecyloxysulfonyl,2-ethylhexyloxysulfonyl, phenoxysulfonyl,2,4-di-t-pentylphenoxysulfonyl, methylsulfonyl, octylsulfonyl,2-ethylhexylsulfonyl, dodecylsulfonyl, hexadecylsulfonyl,phenylsulfonyl, 4-nonylphenylsulfonyl and p-toluylsulfonyl), sulfonyloxy(such as dodecylsulfonyloxy and hexadecylsulfonyloxy), sulfinyl (such asmethylsulfinyl, octylsulfinyl, 2-ethylhexylsulfinyl, dodecylsulfinyl,hexade cylsulfinyl, phenylsulfinyl, 4-nonylphenylsulfinyl andp-toluylsulfinyl), thio [such as ethylthio, octylthio, benzylthio,tetradecylthio, 2-(2,4-di-t-pentylphenoxy)ethylthio, phenylthio,2-butoxy-5-t-octylphenylthio and p-tolylthio], acyloxy (such asacetyloxy, benzoyloxy, octadecanoyloxy, p-dodecylamidobenzoyloxy,N-phenylcarbamoyloxy, N-ethylcarbamoyloxy, and cyclohexylcarbonyloxy),amine (such as phenylanilino, 2-chloroanilino, diethylamine ordodecylamine), amine [such as 1-(N-phenylimido)ethyl, N-succinimido or3-benzylhydantoinyl], phosphate (such as dimethylphosphate andethylbutylphosphate), phosphite (such as diethyl and dihexylphosphite),a heterocyclic group, a heterocyclic oxy group or a heterocyclic thiogroup, each of which may be substituted and which contain a 3 to 7membered heterocyclic ring composed of carbon atoms and at least onehetero atom selected from the group consisting of oxygen, nitrogen andsulfur, such as 2-furyl, 2-thienyl, 2-benzimidazolyloxy or2-benzothiazolyl, quaternary ammonium, such as triethylammonium, andsilyloxy (such as trimethylsilyloxy).

If desired, the substituents may themselves be further substituted oneor more times with one or more of the described substituent groups. Theparticular substituents used may be selected by those skilled in the artto attain the desired photographic properties for a specific applicationand can include, for example, hydrophobic groups, solubilizing groups,blocking groups, releasing or releasable groups, etc. Generally, theabove groups and substituents thereof may include those having up to 48carbon atoms, typically 1 to 36 carbon atoms and usually less than 24carbon atoms, but greater numbers are possible depending on theparticular substituents selected.

Some representative compounds of Structure IV are listed in TABLE Ibelow:

                                      TABLE I                                     __________________________________________________________________________                                       CP-1 ##                                       -                                                                                                             CP-2 ##                                       -                                                                                                             CP-3 ##                                       -                                                                                                             CP-4 ##                                       -                                                                                                             CP-5 ##                                       -                                                                                                             CP-6 ##                                       -                                                                                                             CP-7 0##                                      -                                                                                                             CP-8 1##                                      -                                                                                                             CP-9 2##                                      -                                                                                                             CP-10 ##                                      -                                                                                                             CP-11 ##                                      -                                                                                                             CP-12 ##                                      -                                                                                                             CP-13 ##                                      -                                                                                                             CP-14 ##                                      -                                                                                                             CP-15 ##                                      -                                                                                                             CP-16 ##                                      -                                                                                                             CP-17 ##                                      -                                                                                                             CP-181##                                   __________________________________________________________________________

The compounds represented by Structure IV can be provided for thepractice of this invention by preparing them from conventional startingmaterials and using known reaction conditions (for example, as describedin the Potenza et al and Kim et al patents noted above).

Aromatic amines of Structure III used in the practice of the inventionare formed during the process from various aromatic (Ar) carbocyclic orheterocyclyl groups that have a nitro group and up to 4 othersubstituents (Structure II). Useful aromatic compounds include, but arenot limited to, substituted or unsubstituted phenyl, naphthyl, anthryl,pyridinyl, pyridazinyl, triazinyl and isoquinolinyl groups. If there aretwo or more substituents on the aromatic ring (other than the nitrogroup), they can be combined to form a fused ring with the aromatic ringsystem.

Particularly useful Ar groups include phenyl or other 6- to 10-memberedcarbocyclic aryl groups having large ballast groups as a substituent.Such ballast groups generally have at least 12 carbon, oxygen, sulfurand nitrogen atoms in the chain.

Useful Ar groups include those defined as aryl groups for R₁.Representative aryl groups include, but are not limited to, phenyl,alkylphenyl groups, bromophenyl groups, carboxyphenyl groups,cyanophenyl groups, acetylphenyl groups, alkoxyphenyl groups, and othersthat would be readily apparent to one skilled in the art. The preferredaryl groups are substituted and unsubstituted phenyl groups. Usefularomatic heterocyclyl groups have 5 to 12 carbon, nitrogen, oxygen orsulfur atoms in the aromatic ring (or combination of rings) as describedabove. Representative aromatic heterocyclyl groups include, but are notlimited to, pyridinyl and isoquinolinyl.

Useful nitro-substituted aromatic compounds of Structure II cangenerally be obtained from a number of commercial sources includingAldrich Chemical Co., or prepared using conventional starting materialsand reaction conditions (see for example, EP-A-0 779,543 noted above).

Some typical reactants of Structure II are listed below in TABLE II.##STR22##

As noted above, the pyrazolotriazole compounds prepared using thepresent invention can be used as photographic dye forming couplercompounds without further modification. Alternatively, they can be usedas "intermediates" that are further reacted to provide the desiredphotographic dye forming coupler compounds of interest. Examples ofcompounds of Structure I obtained using the method of this invention arelisted below in TABLE III.

                                      TABLE III                                   __________________________________________________________________________                                      P-1 23##                                       -                                                                                                            P-2 24##                                       -                                                                                                            P-3 25##                                       -                                                                                                            P-4 26##                                       -                                                                                                            P-5 27##                                       -                                                                                                            P-6 28##                                       -                                                                                                            P-7 29##                                       -                                                                                                            P-8 30##                                       -                                                                                                            P-9 31##                                       -                                                                                                            P-10 2##                                       -                                                                                                            P-11 3##                                       -                                                                                                            P-12 4##                                       -                                                                                                            P-13 5##                                       -                                                                                                            P-14 6##                                       -                                                                                                            P-1537##                                    __________________________________________________________________________

The general conditions for preparing the compounds of Structure Iinclude a reaction temperature that is at least 25° C., preferably atleast 35° C., and more preferably at least 40° C. The reactiontemperature can be generally up to 65° C., preferably up to 55° C., andmore preferably up to 50° C.

The reaction media can be aqueous, or composed of one or more organicpolar solvents, or a mixture of water and one or more of such solvents.Useful polar organic solvents include, but are not limited to, alcohols(such as isopropanol), alkyl acetates (such as ethyl acetate and propylacetate), tetrahydrofuran and acetonitrile. Particularly useful polarorganic solvents include isopropanol, ethyl acetate, propyl acetate, ormixtures or two or more of these. Isopropanol is most preferred.

Within the reaction mixture is one or more formate salts that includethe alkali metal, ammonium and trialkylammonium salts (wherein the alkylportions of the cations have from 1 to 4 carbon atoms). The ammonium,sodium and potassium salts are most preferred.

The amount of formate salt in the reaction medium is generally at least3 molar equivalents, preferably at least 3.5 molar equivalents, based onthe concentration of the reactants of Structure IV in the medium. Theamount can be generally up to 6 molar equivalents, and preferably up to4.5 molar equivalents, based on the concentration of the reactants ofStructure IV in the reaction medium.

It is essential to include a transition metal catalyst in the reactionmedium in order to promote the conversion of the nitro-substitutedaromatic compound to the corresponding amine. Useful transition metalcatalysts are well known in the art and include, for example, palladium(on carbon), platinum and others that would be readily apparent to oneskilled in the art. The catalysts can also be removed by filtration atthe end of the method.

The compounds of Structures II and IV are generally present initially inthe reaction mixture at a 1:1 stoichiometric ratio, although a higheramount of one or the other reactant can also be used if desired.

If the compounds of Structure I are to be further reacted to provideuseful photographic dye forming coupler compounds, various knownreactions can be used, including but not limited to, acylation (reactionwith an acid chloride), sulfonylation (reaction with a sulfonylchloride), or isocyanation (reaction with an isocyanate) in suitablepositions on the molecules. Details of some useful reactions areprovided, for example, in U.S. Pat. No. 5,565,572 (noted above) andEP-A-0 779,543 (noted above), both incorporated herein by reference withregard to such reaction methods.

The following examples illustrate the practice of this invention whichis not to be limited thereby.

EXAMPLE 1 Comparative Reactions to Form Intermediates

TABLE IV below shows the results for carrying out the noted reactionusing the present invention compared to two known processes. Included inTABLE IV are the hydrogen source for the first reaction, whether theresulting amine was isolated, total solvent volume for both steps, totalreaction time for both steps (does not include isolation time forControl A), and the % isolated "Yield" of the resulting productintermediate P-1.

The individual synthetic procedures are as follows:

Invention: To a stirred solution of Compound NAS-1 (5.0 g, 10.6 mmol) ina mixture of 25 ml of tetrahydrofuran and 25 ml of isopropanol wereadded ammonium formate (2.69 g, 42.6 mmol) and 10% palladium (Pd) oncarbon catalyst (0.5 g, 50% wet). The reaction mixture was heated to 45°C. for 2 hours. Thin layer chromatography TLC, 1:1 ethylacetate:heptane) showed the reaction was complete. Compound CP-1 (2.57g, 10.6 mmol) was then added, and the reaction mixture was allowed tostir an additional 4 hours. It was then cooled to room temperature andpartitioned between 250 ml of propyl acetate and 250 ml of 5% HCl. Theorganic layer was dried over magnesium sulfate and concentrated to anoil. The product was purified by column chromatography on silica using asolvent gradient of 1:4 ethyl acetate:heptane up to 2:3 ethylacetate:heptane to give 5.58 g of an off-white solid. High pressureliquid chromagraphy (HPLC) showed the material to be 86.6% pure. Thematerial was further purified by recrystallization from ethylacetate:heptane 1:7 to afford 4.15 g of Compound P-1 as a white solid(63% yield).

Control A: A solution of Compound NAS-1 (5.0 g, 10.6 mmol) in a mixtureof 25 ml of tetrahydrofuran and 25 ml of isopropanol was treated with10% palladium on carbon catalyst (0.5 g, 50% wet). This mixture wasplaced on a Parr hydrogenator under 50 psi (3.5 kg-force/cm²) ofhydrogen. After 2.5 hours, the reaction mixture was removed. TLC (1:1ethyl acetate:heptane) showed the reaction was complete. The catalystwas removed by filtration through a CELITE™ pad that was then washedwith a mixture of the organic solvents. The filtrate was concentratedunder reduced pressure to give an oil that was then dissolved intetrahydrofuran (50 ml). Compound CP-1 (2.57 g, 10.6 mmol) andtriethylamine (1.47 mL, 10.6 mmol) were added. The reaction mixture washeated to reflux for 5 hours, cooled to room temperature, andpartitioned between 250 ml of propyl acetate and 250 ml of 5% HCl. Theorganic layer was dried over magnesium sulfate and concentrated to darkoil. The product was purified by chromatography on silica with a solventgradient of 1:4 ethyl acetate:heptane up to 1:1 ethyl acetate:heptane togive 5.12 g of an off-white solid. This material was further purified byrecrystallization from ethyl acetate:heptane 1:7 to afford 3.69 g ofCompound P-1 as a white solid (56% yield).

Control B: To a stirred solution of Compound NAS-1 (5.0 g, 10.6 mmol) ina mixture of 25 ml of tetrahydrofuran and 25 ml of isopropanol under anitrogen atmosphere was added 10% palladium on carbon catalyst (0.5 g,50% wet). The reaction mixture was heated to 55° C., and hypophosphorousacid (5.6 ml, 42.6 mmol, 50% aqueous solution) was added dropwise over 5minutes. TLC after 4 hours showed that starting material remained so anadditional 0.2 g of catalyst and 2.8 ml of hypophosphorous acid wereadded. After an additional 2.5 hours, TLC showed the reaction formingthe aromatic amine was complete. Compound CP-1 (2.57 g, 10.6 mmol) wasthen added, and the reaction mixture was allowed to stir an additional14 hours at 55° C. The reaction mixture was cooled to room temperature,and the solvents were removed under reduced pressure. The resultingresidue was partitioned between 250 ml of propyl acetate and 250 ml ofwater. The layers were separated and the organic layer was washed withbrine and concentrated. The resulting mixture was purified bychromatography on silica with a solvent gradient of 1:4 ethylacetate:heptane up to 100% ethyl acetate. The major product that wasisolated required a second chromatography to purify. The isolate productwas identified as the amine intermediate (1.9 g, 41% yield), not thedesired Compound P-1.

It can be seen from TABLE IV that the present invention provided a 63%yield of desired product without isolation of the intermediate aromaticamine. Somewhat lower yield was obtained for Control A, but the methodrequired isolation of the aromatic amine, considerably lengthening theprocess. Control B shows the use of hypophosphorous acid as the hydrogendonor in the first step, and no isolation of the aromatic amine.However, no reaction occurred to produce the desired product, but about41% of the aromatic amine was isolated at the end of the method.Obviously, the phosphoric acid by-product from hypophosphorous acid didnot promote reaction of the aromatic amine with the compound ofStructure IV. Thus, not every known hydrogen transfer source willprovide by-products that will then promote the formation of compounds ofStructure I in a single reaction medium.

                  TABLE IV                                                        ______________________________________                                          #STR38##                                                                       -                                                                              #STR39##                                                                     -                                                                                  #STR40##                                                                 -                             Total                                           Hydrogen Isolation solvent Total                                             Reaction Source of amine volume reaction time Yield                         ______________________________________                                          Example 1 (NH.sub.4).sup.+ HCOO No 50 ml   6 hours 63%                        Control A H.sub.2 Yes 100 ml  7.5 hours 56%                                   Control B H.sub.3 PO.sub.2 No 50 ml  17 hours  0%                           ______________________________________                                    

In the following examples of the invention, all compounds werecharacterized by spectral methods including mass spectroscopy and NMR.HPLC analysis was used to determine the purity of the isolated compoundsas well as to monitor the progress of the reactions.

EXAMPLE 2 Preparation of Compound P-1:

To a stirred mixture of Compound NAS-1 (47.0 g, 0.10 mol) in ethylacetate (300 ml) and isopropanol (60 ml) was added ammonium formate(25.2 g, 0.40 mol) followed by 5% palladium on carbon catalyst (dry)(2.0 g). The reaction mixture was warmed to 45° C. for 2 hours. TLC(45:30:1 toluene:dioxane:acetic acid) showed the reaction was notcomplete. An additional 1 g of catalyst was added and the reaction washeated to 50° C. until all of the starting material was consumed. Thereaction was cooled to room temperature and Compound CP-1 (24.3 g, 0.10mol) was added. The resulting reaction mixture was warmed to 40° C.overnight. TLC showed some aniline intermediate remained, but all ofCompound CP-1 had been consumed. An additional 2.4 g of Compound CP-1was added and the reaction was stirred at 40° C. for 2 hours. Thereaction mixture was then cooled to room temperature, washed with 5% HCland then washed with brine. The organic layer was dried over magnesiumsulfate, and concentrated under reduced pressure. The product waspurified by crystallization from ethyl acetate:heptane (1:7) to yield 48g (77%) of Compound P-1.

EXAMPLE 3 Preparation of Compound P-3:

To a stirred mixture of Compound NAS-1 (24.0 g, 0.05 mol) in ethylacetate (150 ml) and isopropanol (35 ml) was added ammonium formate(12.5 g, 0.20 mol) followed by 5% palladium on carbon catalyst (dry)(1.0 g). The reaction mixture was warmed to 50° C. for 3 hours. TLC(system 12) showed that the reaction was not complete. An additional 1.0g of catalyst was added and the reaction was heated to 50° C. overnight.The reaction mixture was cooled to room temperature and Compound CP-5(15.3 g, 0.05 mol) was added. The reaction mixture was then warmed to40° C. overnight. TLC (ethyl acetate) showed that some anilineintermediate remained, but all of Compound CP-5 had been consumed. Anadditional 1.5 g of Compound CP-5 was added and the reaction was stirredat 40° C. for 2 hours. The reaction mixture was then cooled to roomtemperature, washed with 5% HCl followed by washing with brine. Theorganic layer was dried over magnesium sulfate, and concentrated underreduced pressure. The product was purified by recrystallization fromethyl acetate/acetonitrile to give 24.8 g (73%) of Compound P-3 as ayellow solid.

EXAMPLE 4 Preparation of Compound P-9:

To a stirred mixture of Compound NAS-8 (39.9 g, 0.10 mol) in ethylacetate (200 ml) and isopropanol (50 ml) was added ammonium formate(27.7 g, 0.44 mol) followed by 5% palladium on carbon catalyst (dry)(2.0 g). The reaction mixture was warmed to 50° C. overnight. TLC showedthat the reaction to form the aniline intermediate was complete.Compound CP-5 (30.5 g, 0.10 mol) was then added, and the reactionmixture was stirred at 50° C. for 4 hours. The reaction mixture waspartitioned between 1.0 molar HCl (200 ml) and ethyl acetate (50 ml).The organic layer was dried over magnesium sulfate, and concentratedunder reduced pressure. The product was purified by slow crystallizationfrom acetonitrile to provide 45.4 g (74.1%) of Compound P-9.

EXAMPLE 5 Preparation of Compound P-14:

To a stirred mixture of Compound NAS-1 (10.0 g, 0.027 mol) intetrahydrofuran (40 ml) and isopropanol (25 ml) was added ammoniumformate (7.5 g, 0.118 mol) followed by 5% palladium on carbon catalyst(dry) (0.4 g). The reaction mixture was warmed to 40° C. for 3.5 hours.TLC showed that the reaction to form the aniline intermediate wascomplete. Compound CP-1 (6.8 g, 0.028 mol) was then added, and thereaction mixture was stirred at 40° C. for 4 hours. The reaction mixturewas partitioned 1.0 molar HCl (100 ml) and ethyl acetate (50 ml). Theorganic layer was dried over magnesium sulfate, and concentrated underreduced pressure. The product was purified by slow crystallization fromacetonitrile (70 ml) to provide 54.2 g (61%) of Compound P-14.

EXAMPLE 6 Preparation of Compound P-15

To a stirred mixture of Compound NAS-8 (25.78 g, 0.065 mol) in ethylacetate (125 ml) and isopropanol (25 ml) was added ammonium formate(16.3 g, 0.26 mol) followed by 5% palladium on carbon catalyst (dry)(1.0 g). The reaction mixture was warmed to 40° C. for 3.5 hours. TLC(system 12) showed that the reaction to form the aniline intermediatewas complete. Compound CP-1 (14.6 g, 0.060 mol) was then added, and thereaction mixture was stirred at 40° C. for 4 hours. It was thenpartitioned between 1.0 molar HCl (200 ml) and ethyl acetate (50 ml).The organic layer was dried over magnesium sulfate, and concentratedunder reduced pressure. The product was purified by slow crystallizationfrom acetonitrile to provide 24.7 g (74.7%) of Compound P-15.

EXAMPLE 7 Preparation of Compound P-16

To a stirred mixture of Compound NAS-11 (43.5 g, 0.12 mol) in ethylacetate (250 ml) and isopropanol (60 ml) was added ammonium formate(29.5 g, 0.47 mol) followed by 5% palladium on carbon catalyst (3.5 g,50% wet). The reaction mixture was warmed to 45° C. overnight. TLCshowed that the reaction to form the aniline intermediate was complete.Compound CP-5 (36.6 g, 0.12 mol) was then added and the reaction mixturewas stirred at 40° C. for 6 hours. It was then was partitioned between1.0 molar HCl (100 ml) and ethyl acetate (50 ml). The organic layer wasdried over magnesium sulfate, and concentrated under reduced pressure.The product was purified by slow crystallization from acetonitrile toprovide 43.3 g (62%) of Compound P-16.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

We claim:
 1. A method of preparing a pyrazolotriazole dye formingcoupler compound comprising:A) forming a compound of Structure I in asingle reaction medium by reacting a nitro-substituted aromatic compoundNO,--AR with a compound of ##STR41## wherein Ar is an aromatic group, R₁is an alkyl, aryl, alkoxy, aryloxy, acyl or amido group, R₂ is hydrogenor an alkyl or aryl group, X is hydrogen or a coupling-off group or aprecursor thereof, and Y is a leaving group that is capable of beingreplaced in an elimination-addition reaction, whereby saidnitro-substituted aromatic compound is converted to the correspondingaromatic amine that is then, without isolation from said single reactionmedium, reacted with said compound of Structure IV, and B) furtherreacting the compound of Structure I obtained in step A in an acylation,sulfonylation or isocyanation reaction to form a pyrazolotriazole dyeforming coupler compound.
 2. The method of claim 1 wherein step A iscarried out at a temperature of from about 20 to about 65° C.
 3. Themethod of claim 1 wherein said nitro-substituted aromatic compound is anitro-substituted phenyl, naphthyl, anthryl, pyridinyl, pyridazinyl,triazinyl, or isoquinolinyl group having a nitro group and up to 4 othersubstituents on the aromatic ring.
 4. The method of claim 3 wherein saidnitro-substituted aromatic compound is a nitro-substituted phenyl group.5. The method of claim 1 wherein said nitro-substituted aromaticcompound is ##STR42##
 6. The method of claim 1 wherein R₁ is an alkyl,aryl, amido, alkoxy or aryloxy group, R₂ is an alkyl or aryl group, X ishydrogen, halo, or an alkylthiol, arylthiol or phenoxy group, and Y ishalo, or an aryloxy, acyloxy or alkoxy group.
 7. The method of claim 6wherein R₁ is an alkyl, phenyl or phenoxy group, R₂ is a phenyl or alkylgroup, X is hydrogen, chloro, phenoxy or carboethoxyethylthio, and Y ishalo, or a p-nitrophenoxy or acetoxy group.
 8. The method of claim 1wherein said formate salt is present in an amount of from about 3 toabout 6 molar equivalents based on the concentration of the compound ofStructure IV, and said reaction medium further comprises a transitionmetal catalyst.
 9. The method of claim 1 wherein said reaction mediumcomprises water, ethyl acetate, propyl acetate, isopropanol,tetrahydrofuran, acetonitrile, or a mixture of any two or more of thesesolvents.
 10. The method of claim 1 wherein the compound of Structure IVis